David Rudisha ruled out of world championships by knee injury
Olympic 800m champion David Rudisha has been forced to pull out of the world championships because of a knee injury.
Last Updated: 16/07/13 1:23pm
The Kenyan , one of the superstars of the London Olympics, had given himself as long as possible to recover from the problem but he has been forced to admit defeat.
Rudisha has not trained for six weeks in a bid to recover in time for next month's Moscow meeting.
His coach Colm O'Connell said: "He has improved quite a lot but we didn't want to do a crash course between now and the world championships, which may aggravate the injury."
Rudisha first felt pain in his knee at the Adidas Grand Prix in New York in May.